In general, a wireless communication terminal in a blood sugar meter system based on an asynchronous transmission mode receives local time zone information (i.e., standard time of a specific region) from a local base station of a public land mobile network (PLMN) and receives changed local standard time information from a corresponding local base station if the wireless communication terminal moves to another time zone. Thus, a wireless communication terminal user has to adjust the reference time of the wireless communication terminal in person.
In order to resolve inconvenience that the wireless communication terminal user in the mobile communication system based on the asynchronous transmission mode has to adjust the reference time of a mobile communication terminal in person as described above, there is a method of receiving network identity and time zone (NITZ) information from the PLMN to update the reference time of the wireless communication terminal.
The wireless communication terminal in the wireless communication system based on the asynchronous transmission mode receives the NITZ information from the PLMN in the following cases: 1) when the wireless communication terminal registers with the PLMN, 2) when the wireless communication terminal moves to another local time zone, 3) when the local time zone of the PLMN is changed, 4) when the network identity of the PLMN is changed, and 5) when the wireless communication terminal sets up a call with (accesses) the PLMN.
According to the method of updating the reference time of the wireless communication terminal in the wireless communication system based on a typical asynchronous transmission mode, when the NITZ information is received form the PLMN as described above, a message “NITZ information has been received. Do you want to change the system time of the wireless communication terminal according to new NITZ information” is displayed on the screen of the display unit of the wireless communication terminal, and then when a user of the wireless communication terminal inputs a command to change the system time of the wireless communication terminal (selects a ‘yes’ key), the wireless communication terminal reboots and automatically updates the system time of the wireless communication terminal based on the new NITZ information.
However, the method of updating the reference time in the wireless communication module based on the typical asynchronous transmission mode as described above has a limitation in that it involves inconvenience of use because a device including the wireless communication module has to be rebooted in order to automatically update the reference time of the wireless communication module according to the new NITZ information.
Also, a blood sugar meter with the wireless communication module focuses on the function of transmitting blood sugar metering data and ignores the actual effective components of the metered blood sugar metering data.
In particular, when there is a certain difference between when blood sugar is metered and when a metering value is transmitted, and when several times in the same country such as North America have certain differences, a metered time varies depending on where a user is, and when information on a time difference between where a server collecting blood sugar metering data is and where a blood sugar meter is used is not checked, management becomes complex.